2021 journal article
Energy Decomposition Analysis of Lewis Acid/Base Adducts and Frustrated Lewis Pairs: The Use of E-Orb/E-Steric Ratios as a Reaction Parameter
INORGANIC CHEMISTRY, 60(18), 13797β13805.
The nature of bonding in classical adducts and frustrated Lewis pairs (FLPs) of oxorhenium and nitridorhenium complexes with B(C6F5)3 was investigated computationally (B3PW91-D3). These studies have revealed that the primary noncovalent interaction (NCI) in the FLPs involves lone pair/Ο interactions between the terminal Mβ‘X bond and the aromatic C6F5 ring in B(C6F5)3. Energy decomposition analyses on classical adducts and FLPs reveal that these species can be defined by the ratio (EOrb/ESteric) of covalent-to-noncovalent contributions to the total interaction energy, EInt. This type of analysis reveals that values for FLPs exist in a narrow range (1.2β2.5), with values for adducts significantly outside this range. The application of this method to other main-group combinations of Lewis acids and bases that have been shown to exhibit FLP reactivity yields similar results. These data suggest that similar NCIs are present in both transition-metal and main-group FLPs, especially where Lewis acids such as B(C6F5)3 are utilized.